Powertrain, generic (extended)

P2C48 Coolant Pump C Control Circuit Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2C48 is a performance check on coolant pump C: the pump is driven, but what it draws or delivers does not match the request. GM uses it in its diesel tables, where pump C is the electric pump of the low-temperature loop: 20OBDG04 estimates the phase current expected at the actual pump speed and flags an error above 4 A for more than 5 s (5 failures in 8 samples), 25OBDG04A above 1 A with the pump over 2,800 rpm (10 of 12); both type B, two trips. In 19OBDG07 GM assigns P2C48 to the pump for the charge air cooler, using a speed-dependent current window. Bulletin 21-NA-265 (Silverado/Sierra 2500/3500 HD 2020–2022, L5P) links P2C48 and a coolant leak to the fuel cooler hose rubbing on the front drive shaft. Underspeed is P2BA0.

Likely causes

Low coolant or air in the low-temperature loop, e.g. from a chafed hose (GM 21-NA-265)
Worn, sluggish or partly blocked pump
Fault in the pump's integrated motor electronics
Weak supply from the powertrain relay or poor ground

Symptoms

  • Check engine light after two trips
  • Coolant leak under the vehicle
  • Higher intake air or fuel temperature, possibly reduced power

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–900
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

coolant pump cwiring harnessecm

Related codes

P2BA0P26F4P26F8P26FAP2C49P2601

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.